1. Field of the Invention
This invention relates, generally, to surgical tools. More particularly, it relates to an apparatus that implants radioactive seeds into a prostate gland or other internal organ.
2. Description of the Prior Art
U.S. Pat. No. 6,213,932 to the present inventor includes a description of the prior art in this field up to the time of its filing. That patent is hereby incorporated into this disclosure by reference.
The invention disclosed in that patent application is the most relevant prior art to the present disclosure. That invention includes an elongate barrel having a radially extending opening formed therein for reception of a cartridge that holds a plurality of radioactive seeds for implanting in a cancerous gland or organ. The cartridge includes a loop-shaped bias means having a first end formed integrally with the cartridge and a second end that is slideably received within the cartridge. The second end bears against the seeds stacked in the cartridge and thus urges the lowermost seed in the cartridge to enter a seed discharge chamber within the elongate barrel. A plunger rod is introduced into an open trailing end of the elongate barrel and shoves a lowermost seed out of the seed discharge chamber into a needle, positioned at the leading end of the elongate barrel, that is inserted within the gland or organ to be treated. The needle can be retracted while the seed is held motionless by the plunger rod or the seed can be pushed out of the end of the needle. After a seed has been implanted by this method, the plunger rod is retracted to the trailing end of the elongate barrel so that the bias means may urge another seed from the lowermost end of the cartridge into the seed discharge chamber and the process is then repeated.
While this earlier device overcame the limitations of the prior art devices that were extant at the time of the invention of said earlier device, a very astute observer could find a limitation of that device. Specifically, the loop-shaped bias means lies in a plane that bisects the longitudinal axis of symmetry of the elongate barrel. Accordingly, the loop-shaped part thereof has a substantial longitudinal extent. Thus, only one of said bias means can be accommodated along the longitudinal extent of said elongate barrel. Although a cartridge might hold up to fifteen to sixteen seeds, it is not uncommon for a single procedure to require seventy to one hundred seeds. This means that the physician is required to introduce a new fully-loaded cartridge several times during the course of a procedure. These cartridges are usually kept in a shielded container apart from the applicator. To reload the applicator requires disengagement of the empty cartridge, retrieval of a full cartridge from a shielded container, and re-insertion of the full cartridge into the applicator. During this process, the physician""s eyes and attention are taken away from the needle and the applicator. This awkward reloading process may result in jiggling of the instruments causing movement of the cutting edges of the needle tip within the prostate gland or other internal organ. Such movement is undesirable.
What is needed, then, is an improved design that substantially reduces the number of times a physician has to divert attention and re-load a new cartridge into the elongate barrel. More particularly, what is needed is: 1) a way to increase the seed-carrying capacity of the cartridge; 2) to increase the cartridge-carrying capacity of the applicator; and 3) better shielding of the radioactive seeds from physicians and operating room personnel.
However, in view of the prior art considered as a whole at the time the present invention was made, it was not obvious to those of ordinary skill in the pertinent art how the needs for enhanced seed and cartridge capacity and improved shielding could be fulfilled.
The longstanding but heretofore unfulfilled need for an interstitial brachytherapy device having an increased seed and cartridge capacity and improved shielding, thus making it easy and expedient for a physician to reload, is now met by a new, useful, and nonobvious invention. The novel interstitial brachytherapy device of this invention includes an applicator having a number of novel and advantageous features. The novel applicator is easily disassembled for cleaning, made of a clear plastic material that enables its internal operation to be viewed, and provides substantial radiation shielding of seeds held therewithin. The novel applicator has an elongate barrel of predetermined longitudinal extent. An elongate throughbore is formed in the elongate barrel in parallel relation to a longitudinal axis of symmetry thereof. A manually-operated, elongate plunger rod is slideably mounted in the elongate throughbore and a hollow needle is detachably secured to the elongate barrel at a leading end thereof. A clear plastic tube connects the seed discharge chamber of the cartridge to the lumen (internal diameter) of the needle. A plurality of slots is formed in the elongate barrel, said slots being longitudinally spaced apart from one another.
A plurality of cartridges is releasably coupled to the elongate barrel. Each of the cartridges has a leading end releasably engaged to an associated slot of the plurality of slots. Each cartridge includes a hollow housing adapted to hold a plurality of radioactive seeds in substantially vertically stacked relation to one another.
The novel structure further includes a handle having an elongate neck depending therefrom. The neck is adapted to be slideably received within the hollow housing and has a leading end adapted to abut an uppermost radioactive seed of said plurality of radioactive seeds. The handle and neck are made of an opaque radiation shielding material which shields the plurality of seeds in an upward direction. A bias means has a leading end engaged to the hollow housing and a trailing end engaged to the handle so that the bias means urges the neck to bear against the plurality of radioactive seeds and to drive them toward their associated seed discharge chamber.
In a preferred embodiment, the bias means is a pair of coil springs having respective trailing ends releasably secured to opposite sides of the handle and having respective leading ends releasably secured to opposite sides of the hollow housing.
In an alternative embodiment, the bias means is a pair of flexible and resilient plastic members of sinusoidal construction. Each of the plastic members has a first end integrally formed with the handle and a second end integrally formed with the hollow housing.
Each cartridge that forms a part of the novel interstitial brachytherepy device is provided in the form of a hollow housing having a generally parallelepiped construction. Each hollow housing has a vertical extent substantially exceeding its respective width and depth extents and is adapted to receive a plurality of radioactive seeds that are vertically stacked therewithin.
The hollow housing may be made of transparent plastic so that the number of radioactive seeds within the housing is ascertainable upon visual inspection of the housing. Alternatively, the housing may be shielded against radiation and therefore be of opaque construction. Since the cartridge body is made in two parts (main housing and front cover), the main housing could be opaque offering protective shielding (along with the handle) on five of the six sides of the seeds in the hollow housing. The front cover could be clear, thereby enabling visual verification of the seeds, or it could also be opaque and shielded. Such an embodiment would provide a completely shielded cartridge heretofore unknown to the art.
When the housing is opaque, a plurality of vertically spaced apart symbols are provided along the extent of the neck so that when the neck is disposed within the hollow housing the number of visible symbols on the neck represents the number of radioactive seeds within the housing.
The novel method for implanting radioactive seeds in a prostate gland or other internal organ includes the steps of preloading a plurality of cartridges with a plurality of radioactive seeds, forming a seed discharge chamber in a preselected end of each of the cartridges, providing an elongate applicator having an elongate throughbore formed therein, mounting a hollow needle at a leading end of the applicator, forming a plurality of slots in the applicator along its longitudinal extent so that the slots are longitudinally spaced apart from one another, inserting a cartridge into each of the slots, thereby providing ease of reloading, and inserting a plunger rod into the elongate throughbore and driving a seed in the seed discharge chamber through a connecting tube affixed to the throughbore of the applicator and through the needle mounted to the nose of the applicator into the prostate gland or other internal organ.
As the cartridges are emptied, they can be easily removed and a full cartridge installed due to the close proximity of stored full cartridges within the applicator. This allows the physician to better maintain concentration on the surgical procedure. Every seed within the applicator is completely shielded by the applicator itself and the handle and neck of each cartridge, all of which may be made of a suitable shielding material. A completely shielded cartridge is also possible by making all components of the cartridge out of opaque shielding material. However, this sacrifices any visual verification of the seeds within the cartridge and the physician must rely on the indicator symbols provided on the neck of the handle.
It is therefore clear that increasing the seed capacity of an interstitial brachytherapy device is an important object of this invention.
A closely related object is to provide a new cartridge design that enables a plurality of cartridges to be mounted along the longitudinal extent of the elongate barrel of such a device.
Another object is to significantly reduce radiation exposure by providing the applicator and cartridge with substantial shielding capabilities.
These and other important objects, advantages, and features of the invention will become clear as this description proceeds.
The invention accordingly comprises the features of construction, combination of elements, and arrangement of parts that will be exemplified in the description set forth hereinafter and the scope of the invention will be indicated in the claims.